A conventional packing sheet or cloth may be formed with a plurality of cells filled with air in each cell on a substrate film or sheet material. Such a cellular packing sheet may be used for packing articles in the sheet to prevent damage or breakage of the articles to be packed. However, if such a packing sheet with air cells formed on the sheet is used for cushioning device such as for serving as an insole used in a footwear or for cushioning a user's body for leaning, seating or wearing purpose, the air-filled cells may be easily broken to lose their cushioning effect.
If a substrate sheet is formed with a plurality of protrusions on the sheet such as by integral molding of plastic processing, the protrusions may still have some hardness or rigidity to possibly stick a user to cause his or her pain when wearing, seating or leaning on such a sheet with protrusions formed thereon.
The present inventor has found the drawbacks of the conventional cushioning sheet, and invented the present cushioning device having liquid cells formed thereon.